The invention relates to a trailer coupling comprising a mounting unit which is fixedly connectable to a vehicle body; a pivot bearing unit, provided on the mounting unit, having a pivot bearing base which is fixedly connected to the mounting unit, and having a pivot element which is pivotable about a pivot axis, relative to the pivot bearing base, between a working position and a rest position, and is displaceable in the direction of the pivot axis between a fixed position and a pivot position; a ball neck which at one end is mounted on the pivot element and which at the other end carries a coupling ball, and which, due to the pivotability of the pivot element, is pivotable about the pivot axis between the working position and the rest position, and due to the displaceability of the pivot element is displaceable between the fixed position and the pivot position; a fixing unit which in the fixed position of the pivot element fixes the pivot element, and thus also the ball neck, relative to the pivot bearing base in a rotationally fixed manner by means of positive-fit elements, and in the pivot position allows pivoting of the pivot element; and a locking unit, which acts axially against a displacement in the direction of the pivot axis, by means of which, in the fixed position, the fixing unit is fixable against a movement in the direction of the pivot position.
These types of trailer couplings are known from the prior art.
For such pivotable trailer couplings, there is a fundamental need to fix the ball neck together with the pivot element on the pivot axis in a rotationally fixed manner as stably as possible in the working position, and to achieve the most cost-effective and space-saving design possible.